Australopithecus afarensis “Australopithecus afarensis” is one of the oldest know hominin species. Thought to have been primarily a vegetarian, possibly a scavenger, it lived in dry uplands and around wooded lake shores. Australopithecus afarensis (meaning “southern Ape from Afar”) possessed a combination of ape-like and human-like traits. Slender and small-brained, it had large, prominent teeth and walked upright, but had long, strong arms and curved fingers, making it adept for life in the trees. No direct evidence of tool making has been found but tools dated to the period in which lived have been found near A. afarensis fossil sites. Nickname: Lucy.
Geologic Age About 3.9 million to 3 million years. Size: males: 4 feet 11 inches, 99 pounds. females: 3 feet 5 inches tall, 64 pounds. Males are about the same size as pygmy men in Central Africa. Brain Size: 400 to 500 cubic centimeters. One third the size of a human brain (1,350 cubic centimeters) and about the same size as a chimp brain (390 cubic centimeters). Perhaps same intelligence of an ape. Linkage to Modern Man: Skeletal features indicate she was on the line that lead to the human genus, Homo.
Discovery Sites: Lucy was discovered near Hadar, Ethiopia. The skeleton is housed at the National Museum of Ethiopia in Addis Ababa. Remains of 60 “A afarenis” individuals have been discovered at Laetoli, Tanzania. Remains have also been found in the Aramis and Omo areas in Ethiopia and Lake Turkana in Kenya.
One of the surprising things about A. afarensis is that it was a surprisingly durable creature, surviving for nearly 900,000 years unchanged, between 3.9 and 3 million years ago. In contrast modern man has only been around for 100,000 to 200,000 years and Neanderthals existed for about 300,000 years. A. afarensis is believed to have evolved into other Australopithecus species which eventually died out. Some scientists believe it evolved into other hominin species after a long period with a dryer, cooler climate. These hominins in turn developed into “ Homo” species. [Source: John Noble Wilford, New York Times]
"Lucy" is the most famous example of Australopithecus afarensis. She was discovered in 1974 by Donald Johanson of Arizona State University in the Afar region of Ethiopia. He and his student, Tom Gray, were searching for ancient animal bones on the parched terrain near the village of Hadar in northern Ethiopia. The chance finding of a piece of arm bone led them to uncover more remains of an ape-like animal. Eventually, they gathered about 40 percent of the skeleton. That evening as the team celebrated at camp the Beatles song Lucy in the Sky with Diamonds came on providing the scientists with a name for their discovery.
Websites and Resources on Hominins and Human Origins: Smithsonian Human Origins Program humanorigins.si.edu ; Institute of Human Origins iho.asu.edu ; Becoming Human University of Arizona site becominghuman.org ; Talk Origins Index talkorigins.org/origins ; Last updated 2006. Hall of Human Origins American Museum of Natural History amnh.org/exhibitions ; Wikipedia article on Human Evolution Wikipedia ; Human Evolution Images evolution-textbook.org; Hominin Species talkorigins.org ; Paleoanthropology Links talkorigins.org ; Britannica Human Evolution britannica.com ; Human Evolution handprint.com ; National Geographic Map of Human Migrations genographic.nationalgeographic.com ; Humin Origins Washington State University wsu.edu/gened/learn-modules ; University of California Museum of Anthropology ucmp.berkeley.edu; BBC The evolution of man" bbc.co.uk/sn/prehistoric_life; "Bones, Stones and Genes: The Origin of Modern Humans" (Video lecture series). Howard Hughes Medical Institute.; Human Evolution Timeline ArchaeologyInfo.com ; Walking with Cavemen (BBC) bbc.co.uk/sn/prehistoric_life ; PBS Evolution: Humans pbs.org/wgbh/evolution/humans; PBS: Human Evolution Library www.pbs.org/wgbh/evolution/library; Human Evolution: you try it, from PBS pbs.org/wgbh/aso/tryit/evolution; John Hawks' Anthropology Weblog johnhawks.net/ ; New Scientist: Human Evolution newscientist.com/article-topic/human-evolution; Fossil Sites and Organizations: The Paleoanthropology Society paleoanthro.org; Institute of Human Origins (Don Johanson's organization) iho.asu.edu/; The Leakey Foundation leakeyfoundation.org; The Stone Age Institute stoneageinstitute.org; The Bradshaw Foundation bradshawfoundation.com ; Turkana Basin Institute turkanabasin.org; Koobi Fora Research Project kfrp.com; Maropeng Cradle of Humankind, South Africa maropeng.co.za ; Blombus Cave Project web.archive.org/web; Journals: Journal of Human Evolution journals.elsevier.com/; American Journal of Physical Anthropology onlinelibrary.wiley.com; Evolutionary Anthropology onlinelibrary.wiley.com; Comptes Rendus Palevol journals.elsevier.com/ ; PaleoAnthropology paleoanthro.org.
Lucy Most of what is known about Australopithecus afarensis is based on "Lucy" — a large part of the skeleton and 40 percent of a skull of a single individual found in 1974 in Hadar in the Great Rift Valley in the Afar region of northern Ethiopia by anthropologist Donald C. Johanson. Lucy's bones have been dated to be 3.18 million years old. She and Ardi (See Ardipithecus) are the most complete old hominin skeletons ever found. Before Lucy was discovered the most complete remains were less than a 100,000 years old. Lucy was named after the Beatle's song “Lucy in the Sky with Diamonds”, which was popular at camp of the discoverers at the time the skeleton was found. Johanson is now director of the Institute of Human Origins at Arizona State University
Lucy was small — about 1.07 meters tall — but fully mature. Her skeleton proved that she walked upright but the lack of a complete skull left many unanswered questions. Some scientists later suggested that Lucy may have been a male because her pelvis hole was heart shaped and too small for a baby to slip through. Peter Schmid and Martin Häusler, anthropologists at the university of Zurich, wrote in the mid 1990s: "Lucy's pelvis has more male traits than female characteristics," they told National Geographic. "The only reason you would say Lucy is a female is her small size."
Lucy has been described as the world’s most famous hominin fossil. After her discovery she was taken to the Cleveland Museum of Natural History, Johansen’s home institution at the time. There molds and casts were made and distributed and the bones themselves were carefully studied. Since 1980 she has resided in a vault at the National Museum of Ethiopia and was only displayed twice.
In 2007, Lucy’s skeleton began a six-year tour of the United States, starting at the Houston Museum of Natural Science, as part of an effort by Ethiopia to raise money for its museums and science projects. Among those who objected to the tour was paleontologist Richard Leakey and the Smithsonian Institution. They said no matter how careful handlers were with the skeleton it was likely to suffer some damage. Leakey called the whole idea of the tour “a form of prostitution.”
Desi and the Three-Year-old Child
The first reasonably complete skull of “Australopithecus afarensis” was discovered in 1992 by American and Israeli scientists at a site near Hadar, Ethiopia, about a mile away from where the skeleton of Lucy was found. Nicknamed "Desi" or "Ricky" as in the husband of Lucille Ball but known to scientists as AL 444-2, the skull belonged a 3-million-year-old male. Reconstructed from nearly 60 fossil fragments, it measured five inches across, making it the largest Australopithecus skull found. AL 444-2 was considerably larger than Lucy.
Lucy and Child AL 444-2 was found by Dr. Yoel Rak of Tel Aviv University and two Ethiopian assistants near their campsite. The newly exposed skull was scattered in more than 200 rock-encrusted fragments. The position of the fragments indicated that they belonged to a single individual. Schmid and Häusler assert that Lucy and Desi belong to two distinct Australopithecus species — one large and one small.
The discovery a three-year-old female “Australopithecus afarensis” in Ethiopia was announced in a September 2006 article in Nature. Dated to 3.3 million years ago and nicknamed the Dikika baby after the region where she was found in December 2000, she is the youngest “Australopithecus afarensis” ever found and the oldest example of the species, predating Lucy by about 150,000 years.
The Dikika baby was discovered by a team lead by Zeresenay Alemseged, an Ethiopian paleoanthropologist at the Max Planck Institute of Evolutionary Anthropology in Leipzig, in region named Dikiko (“nipple” in the local Afar language), just across the Awash River from Hadar where Lucy was found. One of Alemseged’s assistants Tilahu Gebreselassie spotted Dikika’s face peering out from a slope with much of her body entombed in sandstone. Her age of three was determined by the fact that her permanent molars had not yet emerged. [Source: Christopher Sloan, National Geographic, November 2006]
The Dikika baby is not only very old she is the most complete early hominin infant ever found and arguably the best fossil of her species. Unlike Lucy, she has fingers, a foot, a complete torso and face. The shape of her shoulders resembles a young gorilla’s, suggesting that she could climb trees, but the angle of femur from knee to hip is close to that of modern humans, implying she could walk efficiently two legs. She also possessed a hyoid bone, a bone that later became crucial to human speech. Her feet had not yet been extracted from the stone in 2006. Scientists want to see if she had an opposable big toe like a chimps or a unopposable toe like a human, which make walking easier. The brain was 330 cubic centimeters in size, about the same as a three-year-old chimp.
Australopithecus afarensis Skull and Body Features
Lucy skeleton Skull Features: More apelike than human: ape-like face, small ears, large canines, no chin, flared cheeks, flat nose, low forehead, simian-like overhanging browridge over the eyes, pronounced incisors and canine teeth. The mid-face jutted out more than human's face but less than an ape's. The jaw juts forward. Ape-like upper canine fangs extend further out than the other teeth. The large teeth used for grinding vegetation. Teeth examined under a microscope reveal marks made by food stripped off rough vegetables.
Body Features: Dense limb bones indicate great muscular strength. Long ape-like arms; cone-shaped thorax and large belly. Hips, knees and ankles were suited for an upright stance and bent-kneed, two-legged gait somewhat similar to humans. Curved fingers and toes and upward tilting shoulders indicated that her limbs were suited for climbing trees but the arrangement of her hips and pelvis would have had made it difficult to climb trees. Scientists speculate the Lucy spent most of her time on the ground but probably climbed in trees to seek fruit and shelter and possible to sleep. Lucy may . Maybe dark skinned and hairy.
From the waist down “Australopithecus afarensis” is very human-like, with kneecaps similar to those of modern humans and a femur that is angled in such a way to accommodate bipedal movement. From the waist up it is more ape-like. The shoulder blades are similar to those of a gorilla. The fingers are long and curled like a chimpanzee’s. The face is long and projecting and the nose is flat like that of a chimp.
Unlike chimpanzees, Lucy had a relatively small birth canal in her pelvis bone, which made giving birth much more difficult and dangerous for her than a chimpanzee. The smaller birth canal was an adaption made for an upright posture and easier bipedal movement. Human beings are the only species of mammal in which the female is fertile all the times instead of during restricted periods. Some have speculated that the change to year-round fertility may have begun with Australopithecus.
Australopithecus afarensis Size and Sex Differences
A. afarensis reconstruction Lucy's 3.18-million-year-old skeleton suggested a hominin that was only 3½ feet tall and weighed around 65 pounds. The skull of another “ Australopithecus afarensis” found in 1992 indicated a much larger creature — over five feet tall and over 110 pounds.
One nagging question in early hominin anthropology has been whether or not “A. afarensis” was one species or a group of "loosely related species," a question that arose because of the large differences in the size of discovered “ afarensis” bones discovered.
Since a the ulna (a part of the forearm) from the larger hominin discovered in 1992 matched the ulna of Lucy, exactly except it was smaller, it was reasoned that the differences in bone size have attributed to the size difference between males and females.
Henry McHenry of the University of California at Davis believed that hominin stature remained stable between 4 and 2 million years ago, with males tending to be about 50 percent larger than females. This sexual differentiation pattern is consistent with gorilla and orangutan males which weigh almost twice as much as females. Male chimps are only slightly larger than chimp females.
Australopithecus Afarensis Diet Changes 3.5 Million Years Ago
Australopithecus afarensis — the species that includes Lucy — had different diets from their ancestors An analysis teeth from extinct fossils has found that they expanded their diets about 3.5 million years ago to include grasses and possibly animals. Before this, humanlike creatures – or hominins – ate a forest-based diet similar to modern gorillas and chimps. Researchers analysed fossilised tooth enamel of 11 species of hominins and other primates found in East Africa. The findings appeared in four papers published in PNAS journal. [Source: Melissa Hogenboom, BBC News, June 4, 2013 |::|]
Melissa Hogenboom of the BBC wrote: “Like chimpanzees today, many of our early human ancestors lived in forests and ate a diet of leaves and fruits from trees, shrubs and herbs. But scientists have now found that this changed 3.5 million years ago in the species Australopithecus afarensis and Kenyanthropus platyops. Their diet included grasses, sedges, and possibly animals that ate such plants. They also tended to live in the open savannahs of Africa. The new studies show that they not only lived there, but began to consume progressively more foods from the savannahs. |::|
“Researchers looked at samples from 175 hominins of 11 species, ranging from 1.4 to 4.1 million years old. It is not yet clear whether the change in diet included animals, but “the possible diets of some of our hominin kin” has been considerably narrowed down, Dr Matt Sponheimer, lead author of another of the papers, told BBC News. “We now have good evidence that some early hominins began using plant foods that are not used in abundance by living African apes today, and this probably led to a major change in the way they used the landscape. One consequence could be that the dietary expansion led to a habitat expansion, as they could travel to more open habitats more efficiently. We know that many early hominins lived in areas that would not have readily supported chimpanzees with their strong preference for forest fruits. It could also be argued that this dietary expansion was a key element in hominin diversification.” |::|
“The study has also answered, at least in part, what researchers have long been speculating – how so many large species of primate managed to co-exist. “They were not competing for the same foods,” said Prof Thure Cerling from the University of Utah, who led one of the research papers. “All these species who were once in the human lineage, ventured out into this new world of foods 3.5 million years ago, but we don’t yet understand why that is.” |::|
“As well as looking at non-human primates, the researchers analysed fossils from other animals from the same era and did not find any evidence of a change in diet. This combined research highlights a “step towards becoming the modern human”, said Dr Jonathan Wynn from the University of South Florida, who led the analysis of Australopithecus afarensis. “Exploring new environments and testing new foods, ultimately might be correlated with further changes in human history.” These four complementary studies give a persuasive account of shifts in dietary niche in East African hominins, Dr Louise Humphrey from the Natural History Museum in London, told BBC news. |::|
Australopithecus afarensis and Bipedalism
Even though Australopithecus afarensis stood upright, it is far from an open and shut case that it was a completely bipedal creature.”A. afarensis” was probably equally at home in the trees and on the ground. One anthropologist described “A. afarensis” as "bipedal from the waist down and arboreal from the waist up."
The walk of “ afarenis” was a cross between a human and a gorilla. Studies based on Lucy's skeleton and footprints made by 3.6-million-year-old hominins at Laetoli, Tanzania suggest that “aferensis” rotated her trunk and waddled a bit like a gorilla when she walked. Skeletal differences between the sexes seem to indicate that female “ A. afarensis” were better at swinging through the trees while males appeared to better at walking.
Meave Leakey told Time, "They weren't nearly as efficiently upright as we are, and they had a form of locomotion that we don't know today because there isn't anything equivalent.” Zeresenay Alemseged told National Geographic, “I see “A. afarensis” as foraging bipeds but climbing trees when necessary, especially when they were little.”
Australopithecus afarensis and Human Bipedalism
“Australopithecus afarensis” had a broad, human-like pelvis; a foot with an unopposable big toe that lined up with the other toes; and a thigh bone whose top was dense enough to take the vertical stress of the upper body while walking upright.
Scientists at the University of Liverpool think that Lucy probably walked in a similar fashion to modern humans based on entering Lucy's limb proportions into a computer model used in robot design. They found that with her limbs, walking like an ape with a bent-knee, bent-hip posture was less efficient than a human upright posture.
Scientists also think that “ afarensis” was unable to run because Lucy's rib cage had an apelike funnel shape, which means that her lungs could not take in enough oxygen to cool her body efficiently when she ran. They say she would have had to pant like a dog to keep cool and would have died from heat exhaustion if she ran a long way.
Australopithecus afarensis and Ape Bipedalism
“Australopithecus afarensis” had strong arms and shoulders, long arms, flexible joints and curved fingers and toes which allowed it to easily climb trees and grab branches. The hips were pointed slightly sideways. It had a mobile hip, shoulder and ankle joints like chimpanzees.
The shape of “A. afarensis’s feet indicate it may have spent some time living in trees. But its knee joints show it straightened its legs, something that bow-legged knuckle-walking chimps and gorillas can't do. Her free hands were better able to gather food.
Based on the similarities of the structure of Lucy's radius (fore arm) with those of chimpanzee and gorillas, scientists at George Washington University have described Australopithecus afarensis as a "classic knuckle walker." The forearm bone had a ridge, like those found on chimpanzees and gorillas, that allows it to lock in position for easy knucklewalking.
Unlike chimpanzees, whose spines curve forward for the knuckle walking style of advanced primates, “ afarenis” had a spine like modern humans that curved and stood upright to bring the pelvis, legs and feet under the trunk and head, a position ideal of bipedal walking.
A. Afarensis Had Feet Like Modern People and Thus Likely Lived on the Ground
Australopithecus Afarenis had arched feet suggesting it had abandoned life in the trees and lived on the ground. Alok Jha wrote in The Guardian: “The ancestors of humans were walking upright more than 3 million years ago, according to an analysis of a fossilised foot bone found in Ethiopia. The fossil, the fourth metatarsal bone from the species Australopithecus afarensis, shows that this forerunner of early humans had a permanently arched foot like modern humans, a key requirement for an upright gait. Arches in human feet put a spring in our step: they are stiff enough to propel us forward but flexible enough to absorb the shock at the end of each stride. [Source: Alok Jha, The Guardian, February 10, 2011 |=|]
“Scientists already knew that A. afarensis could walk on two feet but were unsure whether the creatures climbed and grasped tree branches as well, much like their own ancestor species and modern nonhuman apes. The fourth metatarsal, described on Thursday in Science, shows that A. afarensis moved around more like modern humans. "Now that we know Lucy and her relatives had arches in their feet, this affects much of what we know about them, from where they lived to what they ate and how they avoided predators," said Carol Ward, a professor of integrative anatomy at the University of Missouri-Columbia who led the analysis of the fossil. “The development of arched feet was a fundamental shift toward the human condition, because it meant giving up the ability to use the big toe for grasping branches, signaling that our ancestors had finally abandoned life in the trees in favour of life on the ground." |=|
“The best-known example of A. afarensis is "Lucy", who lived in eastern Africa more than 3 million years ago. Before that, more than 4.4 million years ago, Ethiopia was populated by Ardipithecus ramidus, which seems to have been a part-time terrestrial biped, though its foot had many of the features of tree-dwelling primates, including a highly mobile big toe. |Unlike other primates, human feet have two arches, which stretch along the length of the foot and across it. Ape feet do not have these arches and are far more flexible, with a mobile large toe that is useful for climbing trees and holding onto branches. |=|
“These ape-like features are not present in the foot of A. afarensis, however. Given that its foot was more like that of modern humans, scientists think that A. afarensis no longer depended on the trees for refuge or resources 3 million years ago. "Arches in the feet are a key component of human-like walking because they absorb shock and also provide a stiff platform so that we can push off from our feet and move forward," said Ward. "People today with 'flat feet' who lack arches have a host of joint problems throughout their skeletons. Understanding that the arch appeared very early in our evolution shows that the unique structure of our feet is fundamental to human locomotion. "If we can understand what we were designed to do and the natural selection that shaped the human skeleton, we can gain insight into how our skeletons work today. Arches in our feet were just as important for our ancestors as they are for us." |=|
“Isabelle De Groote, a palaeontologist at the Natural History Museum in London, said: "These findings confirm that our human ancestors were walking on two legs by about 3.2 million years ago. |=| "Bipedal locomotion or two-legged walking is one of the hallmarks of the human species. Older human fossils still show adaptations to spending some of their time in the trees ... for feeding or nesting, but the evidence here suggests that by 3.2 million years ago one of our ancestors, Australopithecus afarensis, was fully committed to bipedal walking."” |=|
Laetoli footprints A series of 3.6 million-year-old footprints left in volcanic ash by an early hominin were discovered in Laetoli, Tanzania. The 69 prints were made by two adults that appear to have walked side by side. The two sets of prints parallel each other, about a foot apart. The Laetoli footprints were likely made by Australopithecus afarensis individuals. They made headlines in the 1970s as the earliest clear evidence of upright walking by our ancestors.
One set seems to be made by a large male, and the other by a smaller female. Inside the larger prints are prints from a third individual, possible a child. At one point the prints are so close together the hominins could have been holding hands. At another place the small one seems to be walking behind the large one. At another point the smaller one halted in mid stride, perhaps to turned around and look at something.
The Laetoli prints were found with prints from an ancient horse, rhinoceros and antelope. Most anthropologists believe the hominin prints were made by an Australopithecus species but they are not sure whether they were made by afarensis species like Lucy, another known species, or a mystery species whose fossilized bones have not yet been discovered.
The hominins that made the prints had a humanlike stride, wrote paleoanthropologist Donald Johanson in National Geographic: "a strong stride with the heel, followed by a push-off with the big toe to propel the body forward. Their big toes do not splay out from the rest of the foot like the divergent big toes all other primates have."
Zach Zorich wrote in Archaeology magazine: “The 3.6-million-year-old footprints at Laetoli, Tanzania, have fascinated archaeologists since they were discovered in 1976. These prints preserve, in volcanic ash, that most characteristic of behaviors—the act of walking—among early humans. Understanding how early humans moved is important because efficient, upright locomotion was one of the first evolutionary traits that set them apart from other ape species. [Source: Zach Zorich, Archaeology Volume 64 Number 6, November/December 2011]
Significance and Discovery of Laetoli Footprints
Laetoli footprints The Laetoli prints provides the best evidence that early hominin walked like modern humans — body upright, legs striding side by side. Unlike the feet of chimpanzee, which have a splayed toe that separates from the foot like a thumb, the Laetoli tracks are made by feet with all the toes parallel to the axis of the foot (the same as humans).
The large gap between the large toe and the rest of the toe meant the Laetoli creature no longer spent much time climbing trees. There was also no evidence of knuckle walking of any kind. Little Foot, a 3- to 3.5- million-year-old fossil foot from a “ Australopithecus africanus” foot found in South Africa, has an ape-like splayed toe and humanlike ankle which shows that feet ideal of bipedalism evolved slowly.
The Laetoli footprints were discovered in Tanzania by a worker on Mary Leakey's team after falling down trying to dodge a piece of elephant dung flung at him by one of his friends. The footprints were found in rock created by ash created by an eruption from the nearby Sadiman volcano.Accurate dating was made possible by measuring the radioactive decay of particles found in the ash.
A year after the site was discovered, it was covered in river sand filled with seeds of acacia trees that sprouted and almost destroyed the tracks with their roots. In 1993, an emergency operation was launched to kill the trees and excavate the tracks. To preserve the tracks for future generations a granular fill and geo-textile of synthetic material was placed on top of prints at Laetoli to preserve them. The geo-textile kept the granular fill in place while allowing air to circulate and killing off damaging roots with a herbicide that was developed to prevent weeds from growing on foot paths in real east developments.
Short Legs, Running and Aggression
Laetoli footprints recreation The short legs of the Australopithecus were long thought to be needed to climb trees. In a paper published in the journal Evolution in March 2007, David Carrier of the University of Utah argued that short legs more likely evolved to make males better fighters by giving them a lower center of gravity and better balance. Their superior fighting ability in turn made them attractive to females and the trait was passed on.
“Australopiths maintained short legs for two million years because a squat physique and stance helped the males fight over access to females,” Carrier told the Times of London. “With short legs your center of mass is closer to the ground. It’s going to make you more stable so that you can’t be knocked doff your feet as easily. And with short legs you have great leverage as you grapple your opponent.”
Carrier analyzed the heights and limb lengths of modern great apes and compared this data with with levels of aggression. He found that for each primate, apart from modern man, the female had relatively longer legs than males and this suggested a link between leg length and aggression. Modern man is the exception to this rule in that it has long legs and is highly aggressive. Carrier said they “traded advantages of being able to stand their ground for the ability to run away or walk distances.”
Ancient human species such as the australopithecines were unable to run very fast for long periods because they lacked Achilles tendons. With the exception of gibbons all close human relatives — namely chimpanzees, gorillas orangutans — lack Achilles tendons and likely early human ancestors lacked them too. Bill Sellars of the University of Manchester told the Times of London. “Without Achilles tendons you are rubbish at running. You can’t go very fast and you use an awful lot of food to get from A to B. Humans and, strangely, gibbons have great big Achilles tendons...Pursuit running pretty much relies on running...If Lucy has no Achilles tendon she’d be far to inefficient to have been any kind of pursuer. It wouldn’t have stopped her from scavenging, but she wouldn’t have been much of a hunter.” Running is thought to have developed about 2 million years ago. It is a pogo-stick-like motion using tendons in the legs as elastic springs.
3-D Laser Scans Show Laetoli Footprints Were Made Surprisingly Modern Feet
In 2011, a team led by Robin Crompton of the University of Liverpool published a study of the Laetoli footprints using 3-D laser scans that appeared to show that Australopithecus afarensis had anatomically modern feet, approximately 2 million years before they were thought to have evolved. [Source: Zach Zorich, Archaeology Volume 64 Number 6, November/December 2011 ^^]
Zach Zorich wrote in Archaeology magazine: “Crompton's study analyzed 11 of the Laetoli footprints likely to have been made by the same individual, and combined the scanned results to come up with a single composite footprint. The method revealed a detailed picture of how forces were transmitted between the foot and the ground. The composite print was compared to modern ones made by apes and humans walking over a plate that measures downward force. The Laetoli print showed evidence of an arch in the midfoot and a forward-pointing big toe that pushed off with each step, traits similar to those of modern human feet. ^^
New Laetoli Footprints
Thirteen 3.66 million-year-old footprints were found in 2015 about 150 meters away from the famed Laetoli footprints of a similar age found by the Leakeys in the 1970s, The footprints are impressions left in volcanic ash that later hardened into rock. Their comparatively large size, averaging a bit over 26 centimetres, suggest they were made by a male member of the species known as Australopithecus afarensis. [Source: Associated Press, December 14, 2016]
Ian Sample wrote in The Guardian“The markings reveal that the ancient human relatives walked side by side for at least 30 metres. The footprints were laid down in a layer of ash that was subsequently buried, but which when moistened retained the tracks like clay. A first analysis of the footprints suggests that they were made when a male, three females and a child passed through what is now Laetoli in the African country. The individuals almost certainly belong to a species of hairy bipedal ape called Australopithecus afarensis which is known to have lived in the region. The most famous member of the species, known as Lucy, lived in the Hadar area of Ethiopia 3.2 million years ago. A mere 1.1 metre tall, she was tiny in comparison to those who left their marks in Tanzania. The male stood more than half a metre taller, at 165 centimeters (5ft 5in), making him the largest Australopithecus yet recorded. His impressive stature – for his species – led researchers to nickname him Chewie after the towering hairy Wookiee in Star Wars.[Source: Ian Sample, The Guardian, December 14, 2016 |=|]
“Researchers unearthed the tracks by accident when they began to excavate test pits that had been called for as part of an assessment of the impact of building a proposed museum on the site in Tanzania. Marco Cherin, a palaeontologist at the University of Perugia in Italy, helped to excavate the tracks after the first prints were discovered by a team in Tanzania. “When we reached the footprint layer and started to clean it with a soft brush and saw the footprints for the first time, it was really one of the most exciting times of my life,” he said. |=|
“The layer of ash that preserved the tracks has been dated to 3.66 million years old, the same age as a similar sequence of hominin, or human ancestor, footprints found nearby by famed palaeontologist Mary Leakey in the 1970s. Researchers now want to return to the site to dig a trench that links the excavation pits and then work outwards, in the hope of revealing more tracks. “We are pretty sure that at least one more individual is waiting for us, and possibly more. Our goal is to discover new individuals,” Cherin said. |=|
New Laetoli Footprints Made by Five Individuals, Including a Big Male
Initial analysis of new Laetoli footprints suggests that they were made by a male, three females and a child. Ian Sample wrote in The Guardian: “Having uncovered the footprints and measured them, the scientists used a number of mathematical models to calculate the heights of the different individuals. If the scientists are right that the group consisted of a tall male with three adult females and a child, it would bolster the theory that Australopithecus afarensis was polygynous, meaning that, like gorillas, males would have had several female partners at once. The adult females stood about 140 centimeters tall. [Source: Ian Sample, The Guardian, December 14, 2016 |=|]
“Measurements of the length and width of the footprints, the angle of the gait and the stride lengths allowed the scientists to calculate rough weights for the five. The tall male came in at the heaviest, weighing 48.1kg, with the lightest only 28.5kg. “These footprints enrich our knowledge about the most ancient hominin footprints in the world,” Cherin told the Guardian. “But they tell us something about the makers too, in this case that we think there were significant differences between the males and females. This is the most striking thing. A tentative conclusion is that the group consisted of one male, two or three females, and one or two juveniles, which leads us to believe that the male – and therefore other males in the species – had more than one female mate,” Cherin added. Details of the tracks are published in the journal, eLife. |=|
“Giorgio Manzi, director of the archaeological project in Tanzania, said the evidence portrayed several human ancestors moving through the landscape after a volcanic eruption that was followed by rain. “The footprints of one of the new individuals are astonishingly larger than anyone else’s in the group, suggesting that he was a large male member of the species. In fact, the 165 centimeter stature indicated by his footprints makes him the largest Australopithecus specimen identified to date.” In being so short, it seems that Lucy was an outlier.
“William Jungers of Stony Brook University in New York said: “To judge by the profound scientific impact of the first set of Laetoli footprints, we can expect the new ones to figure prominently in future narratives of the origins of humans. They will likely stimulate new research and debate for years to come.” |=|
New Laetoli Footprints: a Big Male and a Harem?
Associated Press reported: “He stood a majestic five-foot-five, weighed around 100 pounds and maybe had a harem. That's what scientists figure from the footprints he left behind some 3.7 million year ago. He's evidently the tallest known member of the pre-human species best known for the fossil skeleton nicknamed "Lucy," reaching a stature no other member of our family tree matched for another 1.5 million years, the researchers say. Researchers named the new creature S1, for the first discovery made at the "S" site. From the footprints, they calculated that he stood about roughly five-foot-five and weighed around about 100 pounds. [Source: Associated Press, December 14, 2016 ^]
“They figured that he loomed at least more than 20 centimetres above the individuals who made the other tracks, and stood maybe 7 centimetres taller than a large A. afarensis specimen previously found in Ethiopia. "Lucy," also from Ethiopia, was much shorter at about 3½ feet. The findings are described in a report released Wednesday by the journal eLife. Authors include Giorgio Manzi of Sapienza University in Rome, Marco Cherin of the University of Perugia in Italy, and others. ^
“Nobody knows the ages or sexes of any of the track-makers, although the size of the latest footprints suggest they were made by a male. It's quite possible that the new discovery means A. afarensis males were a lot bigger than females, with more of a difference than what is seen in modern humans, the researchers say. That's not a new idea, but it's still under debate. The large male-female disparity suggests A. afarensis may have had a gorilla-like social arrangement of one dominant male with a group of females and their offspring, the researchers said. ^
“But not everybody agrees with their analysis of S1's height. Their estimate is suspect, says anthropologist William Jungers, a research associate at the Association Vahatra in Madagascar who wrote a commentary on the study. That's because scientists haven't recovered enough of an A. afarensis foot to reliably calculate height from footprints, he said. Philip Reno, an assistant anthropology professor at Penn State who didn't participate in the new work, said he believed the height estimate was in the right ballpark. But he's not convinced that S1 was really taller than the large Ethiopian A. afarensis. So rather than setting a record, "I think it confirms about the size we thought the big specimens were," Reno said. Manzi and Cherin said they can't be sure S1 was taller than the Ethiopian specimen. "We only suggest," they wrote in an email.” ^
”Kadanuumuu” Confirms Australopithecus afarensis Walked Upright
A. afarensis reconstruction Brendan Borrell wrote in Archaeology magazine, For the last 35 years, the short-legged “Lucy” skeleton has led some scientists to argue that Australopithecus afarensis didn’t stand fully upright or walk like modern humans, and instead got around by “knuckle-walking” like apes. Now, the discovery of a 3.6-million-year-old beanpole on the Ethiopian plains — christened “Kadanuumuu,” or “Big Man — in the Afar language — puts that tired debate to rest. The new fossil demonstrates these early human ancestors were fully bipedal. [Source: Brendan Borrell, Archaeology magazine, January/February 2011]
Many dozens of A. afarensis fossils have been uncovered since Lucy was discovered in 1974, but none as complete as this one. Kadanuumuu’s forearm was first extracted from a hunk of mudstone in February 2005, and subsequent expeditions uncovered an entire knee, part of a pelvis, and well preserved sections of the thorax. [Ibid]
“We have the clavicle, a first rib, a scapula, and the humerus,” says physical anthropologist Bruce Latimer of Case Western Reserve University in Cleveland, Ohio, one of the co-leaders on the dig. “That enables us to say something about how [Kadanuumuu] was using its arm, and it was clearly not using it the way an ape uses it. It finally takes knuckle-walking off the table.” At five and a half feet tall, Kadanuumuu would also have towered two feet over Lucy, lending support to the view that there was a high degree of sexual dimorphism in the species. [Ibid]
Lucy Was an Adept Tree Climber
Scientists using sophisticated CT scanning on Lucy’s fossil bones determined that she spent a lot of time in the trees. Reuters reported: “Researchers announced the results of an intensive analysis of the 3.18 million-year-old fossils of Lucy, a member of a species early in the human evolutionary lineage known as Australopithecus afarensis. The scans of Lucy's arm bones showed they were heavily built, like those of chimpanzees. This indicates that members of this species spent significant time climbing in trees and used their arms to pull themselves up in the branches. [Source: Reuters, December 1, 2016]
Scientists already knew the species' feet were adapted for walking upright on two legs, rather than grasping trees, but had wondered about whether its members still spent time in trees like their ancestors. Chimpanzees, the closest living relative of humans, spend a lot of time in trees. The researchers performed high-resolution X-ray CT scans on Lucy's fossils at the University of Texas and compared the findings to data on the bones of modern humans and chimpanzees. "The debate about whether or not Lucy climbed trees has been raging ever since her discovery 42 years ago this month — our study brings that debate to a close," said University of Texas paleoanthropologist John Kappelman, one of researchers in the study published in the journal PLOS ONE.
Kappelman said: “"It may seem unique from our perspective that early hominins like Lucy combined walking on the ground on two legs with a significant amount of tree climbing, but Lucy didn't know she was unique." Tthe study's lead author, Christopher Ruff, a professor of functional anatomy and evolution at the Johns Hopkins University School of Medicine in Baltimore, said: "Our analysis required well-preserved upper and lower limb bones from the same individual, something very rare in the fossil record."
Lucy Died in a Fall from a Tree?
In 2016 University of Texas paleoanthropologist John Kappelman said that Lucy might have died after falling out of a tree. Kappelman conducted a new analysis of the bones and concluded that a number of cracks found by his team matched the traumatic fractures seen in humans that suffer serious injuries from high falls. The theory was met with scepticism by many researchers, who pointed out that a lot can happen to a skeleton in 3.2 million years. For example, Lucy’s body might have been crushed by stampeding animals before her bones were covered in sediment that changed to rock.
Kappelman hypothesized that Lucy foraged on the ground during the day and sought safety in the trees at night and said her injuries indicated she fell from a height of more than 12 meters. “The consistency of the pattern of fractures with what we see in fall victims leads us to propose that it was a fall that was responsible for Lucy’s death,” Kappelman said. “I think the injuries were so severe that she probably died very rapidly after the fall.” [Source: Ian Sample, The Guardian, December 14, 2016]
But the claims, published in the journal Nature, were widely criticized in academic circles. “There is a myriad of explanations for bone breakage,” Lucy discoverer Donald Johanson of Arizona State University, told The Guardian. “The suggestion that she fell out of a tree is largely a “just-so story” that is neither verifiable nor falsifiable, and therefore unprovable.” Tim White, a paleoanthropologist at the University of California in Berkeley, said the cracks were no more than routine fossil damage. “If paleontologists were to apply the same logic and assertion to the many mammals whose fossilised bones have been distorted by geological forces, we would have everything from gazelles to hippos, rhinos, and elephants climbing and falling from high trees,” he said.
Ian Sample wrote in The Guardian: “Kappelman became intrigued by some of the cracks in Lucy’s bones after examining high resolution x-ray scans of the fossils. The cracks had been described before and put down to natural processes such as erosion and fossilisation. But Kappelman thought there might be another explanation. |=|
“Working with Stephen Pearce, an orthopaedic surgeon, the scientists identified cracks in more than a dozen bones, ranging from the skull and spine to the ankles, shins, knees and pelvis, which look like compressive fractures sustained in a fall. One injury to the right shoulder matches the kind of fracture seen when people instinctively put their arms out to save themselves, the scientists believe. Kappelman calls it “a unique signature” for a fall and evidence that the individual was conscious at the time. |=|
“From the scientists’ calculations, Lucy, who weighed less than 30kg, could have suffered similar injuries in a fall from about 15 metres. If Australopithecus afarensis climbed trees to nest, the animals could have spent hours a day at this or even greater heights. “We know that chimps fall out of trees and often it’s because they step on a branch that turns out to be rotten, and boom, down they come,” said Kappelman. “Based on clinical literature these are severe trauma events. We have not been able to come up with a reasonable way that these could be fractured postmortem with the bones lying on the surface or even if the dead body was being trampled on. If somebody is trampled on the bone breaks in a different way. It doesn’t break compressively,” said Kappelman. |=|
“But Johanson is not impressed. The cracks on Lucy’s bones are similar to the damage seen on other early human and ancient mammal fossils throughout Africa and the rest of the world, he said. “We don’t know how long the fossilisation process takes, but the enormous set of forces placed on the bones during the build up of sediments covering the bones is a significant factor in promoting damage and breakage,” he added.
“One of White’s major complaints is that the scientists fail to prove beyond doubt that the cracks in Lucy’s bones occurred around the time of death. “Such defects created by natural geological forces of sediment pressure and mineral growth are very common in fossil assemblages. They often confuse clinicians and amateurs who imagine them to have happened around the time of death,” White said. “Every single element of the Lucy fossil has cracks. The authors cherry pick the ones that they imagine to be evidence of a fall from a tree, leaving the others unexplained and unexamined.” Kappelman concedes that we can never know for sure what happened. “None of us were there. We didn’t see Lucy die,” he said. “Thinking about testing this idea, it’s hard to get someone to fall out of a tree, but we have tests going on every single day in every emergency room on planet Earth when people walk in with fractures from falls,” he said. |=|
World's Earliest Tools?
In late 2010 Archaeology magazine reported: Paleoanthropologists in Ethiopia may have discovered the earliest evidence of stone-tool use. Some 3.3-million-year old bones found near the site of Dikika have marks that look like they were made by tool-using hominins. If this evidence is legitimate, it could mean that one of the tool-using behaviors — a hallmark of humans — dates back to our relatively small-brained ancestors the Australopithecines. Prior to this discovery, the earliest evidence of tool use had come from the site of Gona, which was occupied by Homo habilis 2.6 million years ago. [Source: Brendan Borrell,Archaeology magazine, November/December 2010]
Curtis Marean of Arizona State University examined the bones, which include a femur with gashes running across the bone. "I could tell within minutes that this was stone-tool-inflicted," he says. A rib bone also appeared to have been pounded open with a stone wielded like a hammer. But when the study was published in Nature in August 2010, the findings were greeted with suspicion.
Manuel Domínguez-Rodrigo of Complutense University in Madrid is an expert in the processes that affect bones as they fossilize. He says he has seen similar marks from Ethiopian bones as old as 6 million years, but believes those marks could have been caused by animals trampling the bones or by crocodile bites. Stanley Ambrose of the University of Illinois at Urbana-Champaign calls the report "premature" and says that excavation of the bone-bearing sediments should be conducted to see if there is other evidence of butchery. Confirmation may come from other material first. "People have fragments from that age that they think are stone-tool modified, but they have just been a little hesitant to step out and make the case," says Marean.
Cut Marks on 3.4-Million-Year-Old Bone: Earliest Evidence of Tools?
In 2009, 3.4-million-year-old bones — found in Dikika, Ethiopia, near site where a Lucy-like hominin was discovered — with slashes, parallel marks and other cut marks that appear to have been made with stone tools, was presented as evidence that stone tools were produced more than 800,000 years than earlier thought and they could have been made by a possible human ancestor such as Lucy (Australopithecus afarenis).
The marks were made on a rib from a cow-like hoofed creature and a thigh bone from a goat-size animal, possibly from an impala, gazelle or antelope. It was argued that someone used stones to trim flesh from bone and perhaps crush bones to get at the marrow inside. It was also argued that this was the earliest evidence of meat and marrow consumption by hominins. No tools were found at that site, so it was unclear whether the marks were made with handmade tools or just naturally sharp rocks. [Source: Charles Q. Choi, Live Science, May 20, 2015]
"We were just walking along when we discovered the two bones," Shannon McPherron, an archaeologist at the Max Planck Institute for Evolutionary Anthropology in Leipzig, told The Guardian. "We picked up the rib fragment, flipped it over and there were these two, clear marks. Soon after, we found the second bone, also with a lot of marks on it. Right away we knew we had something potentially important." [Source: Ian Sample, The Guardian, August 11, 2010]
Jennifer Viegas wrote in Discovery News: “Various types of electron microscopy, along with chemical analysis, determined that cut marks were inflicted while one or more individuals carved meat off the bones with a sharp stone tool. Percussion marks were also created when a stone tool broke open the bones to extract their nutritious marrow. The fossilized bones were found sandwiched between volcanic deposits, which permitted reliable dating of them. Before this discovery, the world’s oldest human evidence for butchery dated to 2.5 million years ago and came from Bouri and Gona, Ethiopia. No human remains were found in association with those fossilized prey bones, but A. afarensis remains were previously unearthed near the recent Afar Region discoveries. [Source: Jennifer Viegas Discovery News, August 11, 2010]
Unlike 2.5-million-year-old stone flakes found Ethiopia in 1997, which were mostly sharp cutting edges or the remains of the tool-making process, the stone tools that made the marks in Dikika were likely used as they were found. Detailed analysis of the cut marks on the bones seemed to indicate they were significantly different from tooth and claw marks made by predators. One of the marks was embedded with a small fragment of stone, according to a report in the journal, Nature.
Tia Ghose wrote in Live Science: “The bones were found several years ago in the history-rich sediments of Dikika, an area in the Awash River valley in Ethiopia,” an arid region that “has yielded some of the best examples of both early hominin fossils and fossils from anatomically modern early humans. Though archaeologists have not found hominin fossils at this particular site, just a few hundred meters away, other research teams previously found the nearly intact skeleton of a 3.3-million-year-old baby girl Australopithecus, dubbed "the Dikika baby" or "Lucy's baby." (The Dikika baby is not truly Lucy's baby, since she lived 100,000 years before Lucy.) [Source: Tia Ghose, Live Science, August 20, 2015]
“At this particular spot, other paleoanthropologists sifting through 3.4-million-year-old sediments found two bones — one from an antelope-size creature and another from a buffalo-size animal — that had a total of 12 distinctive marks. In a 2010 study published in the journal Nature, researchers proposed that someone used a cutting tool to make those marks. But the news was considered shocking: In 2010, the earliest known stone tools, from Gona, Ethiopia, dated to 2.6 million years ago. In 2011, another research group weighed in, writing in a paper in the journal Proceedings of the National Academy of Sciences that the marks on the bones were likely not cut marks, but instead the marks of sediments rubbing over the bones as wild beasts trampled them over the millennia.”
3.3-Million- Year-Old Stone Tools Found in Northern Kenya
In May 2015, researchers announced the discovery of 3.3-million-year-old stone tools found at a site in Kenya, making the idea that tool-making predated all Homo species more acceptable. If it turns tools are indeed tools, the species that made them is unknown although some scientists have speculated it was Australopithecus afarensis (Lucy). Scientists detailed their findings in the May 21, 2015 issue of Nature. Charles Q. Choi of Live Science wrote: “The 3.3-million-year-old stone artifacts are the first direct evidence that early human ancestors may have possessed the mental abilities needed to figure out how to make razor-sharp stone tools. The discovery also rewrites the book on the kind of environmental and evolutionary pressures that drove the emergence of toolmaking. [Source: Charles Q. Choi, Live Science, May 20, 2015]
Until now, the earliest known tools were about 2.8 million years old, the researchers said. The artifacts are by far the oldest handmade stone tools yet discovered — the previous record-holders, known as Oldowan stone tools, were about 2.6 million years old. "We were not surprised to find stone tools older than 2.6 million years, because paleoanthropologists have been saying for the last decade that they should be out there somewhere," Harmand said. "But we were surprised that the tools we found are so much older than the Oldowan, at 3.3 million years old."
“It remains unknown what species made these stone tools. They could have been created by an as-yet-unknown extinct human species, or by Australopithecus, which is currently the leading contender for the ancestor of the human lineage, or by Kenyanthropus, a 3.3-million-year-old skull of which was discovered in 1999 about a half-mile (1 kilometer) from the newfound tools. It remains uncertain exactly how Kenyanthropus relates to either Homo or Australopithecus. "Sometimes the best discoveries are the ones that raise more questions than provide answers," study co-author Jason Lewis, a paleoanthropologist at Stony Brook University and Rutgers University in New Jersey, told Live Science. "In any of these cases the story is equally new and interesting. We are comfortable not having all of the answers now."
“The stone tools were discovered in the desert badlands of northwestern Kenya, where the arid, rocky terrain resembles a New Mexican landscape. The artifacts were found next to Lake Turkana in 2011 almost by accident. "We were driving in the dry riverbed and took the left branch instead of the right, and got off course," Harmand said. "Essentially, we got lost and ended up in a new area that looked promising. Something was really unique about this place, we could tell that this zone had a lot of hidden areas just waiting to be explored." By the end of the 2012 field season, excavations at the site, named Lomekwi 3, had uncovered 149 "Lomekwian" stone artifacts linked with toolmaking. "It is really exciting and very moving to be the first person to pick up a stone artifact since its original maker put it down millions of years ago," Harmand said.
“The researchers tried using stones to knock off and shape so-called flakes or blades — a process known as knapping — to better understand how these Lomekwian stone artifacts might have been made. They concluded the techniques used may represent a stage between the pounding used by earlier hominins and the knapping of later toolmakers. "This is a momentous and well-researched discovery," paleoanthropologist Bernard Wood, a professor of human origins at George Washington University, who was not involved in the study, said in a statement. "I have seen some of these artifacts in the flesh, and I am convinced they were fashioned deliberately." Analysis of carbon isotopes in the soil and animal fossils at the site allowed the scientists to reconstruct what the vegetation there used to be like. This led to another surprise — back then, the area was a partially wooded, shrubby environment.”
Implications of 3.4-Million-Year-Old Tools
Charles Q. Choi of Live Science wrote: “Chimpanzees and monkeys are known to use stones as tools, picking up rocks to hammer open nuts and solve other problems. However, until now, only members of the human lineage — the genus Homo, which includes the modern human species Homo sapiens and extinct humans such as Homo erectus — were thought capable of making stone tools.[Source: Charles Q. Choi, Live Science, May 20, 2015]
If early hominins were using tools so early, that means their cognitive abilities were also more advanced than previously thought, Briana Pobiner, a paleoanthropologist at the Smithsonian Institution, told Live Science. For instance, humans' closest living relatives, chimpanzees, may crack nuts using stones or may sharpen sticks to hunt other primates called bush babies, but they do that with their teeth. Making stone tools involves bashing one stone on another rock to make the desired pointy shape. "To make a stone tool, you use a tool to make a second tool," Pobiner told Live Science.[Source: Tia Ghose, Live Science, August 20, 2015 |]
That's a different cognitive process, she said. "There's a lot of planning and forethought involved," Pobiner said, from picking the right kind of rock, to striking with the tool in just the right way to get the stone flaked off. Either way, the new study, combined with the discovery of similarly aged tools in Kenya, make the notion that ancient human ancestors cut the Dikika bones much more likely, Pobiner said. |
3.4-Million-Year-Old Tools and Australopithecus Afarensis
Ian Sample wrote in The Guardian: “The butchered bones were discovered close to where the skeleton of a probable human ancestor, nicknamed Lucy, was found. Lucy belonged to a species called Australopithecus afarensis and lived in the region around 3.2 million years ago. At the time, the region was warm and wet, with patches of grassland and heavily forested areas populated with early forms of giraffes, monkeys, elephants and rhinos. “"Now, when we imagine Lucy walking around the east African landscape looking for food, we can for the first time imagine her with a stone tool in hand looking for meat," said McPherron. The skeleton of another female, "Selam", was found 200 miles away. [Source: Ian Sample, The Guardian, August 11, 2010 |=|]
“The use of simple stone tools to remove meat and marrow marks a crucial moment in the human story. As the ancestors of early humans turned to meat for sustenance, they were able to grow larger brains which in turn enabled them to make more sophisticated tools. "These bones may take us to the very beginning of that process," said Chris Stringer, head of human origins at the Natural History Museum in London. "What we need from these sites now are evidence of the stone tools themselves, so we can see if they were manufactured or were natural stones that happened to be used for butchery," he added. |=|
“Lucy and others of her species probably carried natural stone tools around with them to use when they encountered a dead animal. "It's not a trivial thing to leave the trees behind, wander out onto this open landscape and start removing flesh and marrow from a carcass. Those same carcasses were attracting carnivores that look at these early hominins as a meal, so they were taking a major risk," said McPherron.” |=|
Jennifer Viegas wrote in Discovery News: “Since the Afar stone tools were transported to the kill or scavenge site from nearly four miles away, A. afarensis must have valued the sharp objects. What’s unclear, however, is whether or not the ancient hominins made the stones themselves, or just picked already sharp stones up from the ground.” [Source: Jennifer Viegas Discovery News, August 11, 2010]
Revised Theory of Toolmaking
Charles Q. Choi of Live Science wrote: “Conventional thinking has been that sophisticated toolmaking came in response to a change in climate that led to shrinking forests and the spread of savannah grasslands. Stone blades likely helped ancient humans get food by helping them cut meat off the carcasses of animals, given how there was then less food such as fruit to be found in the forest. However, these findings suggest that Lomekwian stone tools may have been used for breaking open nuts or tubers, bashing open dead logs to get at insects inside, or maybe something not yet thought of. "The Lomekwi 3 evidence suggests that important evolutionary changes that would later be really important for Homo to survive on the savannah were actually evolving beforehand, in a still-wooded environment," Lewis said.[Source: Charles Q. Choi, Live Science, May 20, 2015]
This discovery also has implications for understanding the evolution of the human brain, researchers said. Toolmaking required a level of dexterity and grip that suggests that changes in the brain and spinal tract needed for such activity could have evolved before 3.3 million years ago. "The capabilities of our ancestors and the environmental forces leading to early stone technology are a great scientific mystery," Richard Potts, director of the Human Origins Program at the Smithsonian's National Museum of Natural History, who was not involved in the research, said in a statement. The newly dated tools "begin to lift the veil on that mystery, at an earlier time than expected."
“The scientists are now looking at the surfaces and edges of the tools under microscopes and with laser scans to try to reconstruct how they were used, "and also studying the sediment in which they were found to search for trace elements or residues of any possible plant or animal tissues that could be left on them after use," Harmand said. The site is still under excavation, and Harmand said other artifacts could exist from early attempts at knapping. "We think there are older, even more rudimentary, stone tools out there to be found, and we will be looking for them over the coming field seasons," he added.”
Image Sources: Wikimedia Commons except Laetoli footprints from Sciencephoto
Text Sources: National Geographic, New York Times, Washington Post, Los Angeles Times, Smithsonian magazine, Nature, Scientific American. Live Science, Discover magazine, Discovery News, Times of London, Natural History magazine, Archaeology magazine, The New Yorker, Time, Newsweek, BBC, The Guardian, Reuters, AP, AFP, and various books and other publications.
Last updated September 2018